Floating head for heat exchangers



July 26, 1938. w. A. STOVER 2,1259132 FLOATING HEAD FOR HEAT EXCHANGERS Filed Feb. 26,1958

INVENTOR WM. STOVER ATTORN EY Patented July 26, .l938

FLOATING HEAD FOB HEAT EXCHANGEBS William A. Stover, Tulsa, Okla., assignor to Petroleum Engineering, Incorporated, Tulsa, Okla., a

corporation of Delaware Application February 26, 1938, Serial No. 192,691

4 Claims.

This invention relates to improvements in shell and tube type heat exchangers, and particularly to such exchangers having floating heads.

The particular improvement contemplated by this invention is concerned with a novel form of floating head structure.

The principal object of this invention is to provide a floating head structure including a tube sheet and closure therefor, the tube sheet having maximum effective area, for reception of tubes to thereby increase the total number of tubes which may be accommodated within a shell of a given diameter and to permit the spacing of tubes in close proximity to the wall of the shell to thereby increase the velocity of the fluid flowing through the shell and outside the tubes whereby the heat transfer coefficient of the heat exchanger is substantially increased.

Since this invention is concerned primarily with a floating head arrangement to be used with the more or less conventional forms of floating head type exchangers, only the floating head structure is shown in the accompanying drawing, since the construction of the other portions of such exchangers, including the shell and the fixed end of tube nest is well known and understood by those skilled in the art.

The advantages of the novel from of floating head construction contemplated by this invention will be readily understood from the following detailed description when read in conjunction.

with the accompanying drawing, which illustrates a preferred form of the device.

In the drawing:

Fig. 1 is a fragmentary view, largely in section, of the floating head end of a heat exchanger,

showing the novel form' of construction of the floating head of this invention and its position within the shell.

Fig. 2 is an expanded view of the floating head consisting of the floating tube sheet, the cap and the clamping device for clamping the cap to the tube sheet.

Fig. 3 is a fragmentary view of a detail of the floating head structure, and

Fig. 4 is a cross-section, in reduced size, of the device taken along line 4-4 of Fig. 1.

Referring to the drawing, Fig. 1 shows the floating head end of an exchanger shell I provided with an encircling flange 2, the end of the shell being closed by a flanged head 3 which is clamped to flange 2 by means of bolts 4. Extending through the end of shell I into head 3 is a tubenest 5, having the ends of the individual tubes extending through a floating tube sheet 6 into which the tube ends are firmly flxed, as by rolling or welding. The ends of the tubes extend beyond the end of the shell into the interior of head 3 and tube sheet 6 is spaced a suflicient distance from the end of the shell to permit free longitudinal movement of the tube sheet and the ends of the tubes relative to the shell with expansion and contraction of the tubes. It will be understood, in accordance with conventional design, that the opposite end of tube nest 5 is fixed in another tube sheet, not

shown, which is in turn rigidly clamped at the.

opposite end of the shell, also not shown, against movement relative to the shell.

Floating tube sheet 6 has a diameter very slightly less than the internal diameter of shell I so that the floating head end of tube nest 5 together with floating tube sheet 6 may be withdrawn readily through the shell in the direction of the fixed end of the tube nest. A groove 1 (Figs. 2 and 3) is cut into the peripheral edge of tube sheet 6 and longitudinally nearer to the face thereof which is adjacent to the end of shell i than to the outer opposite face of the tube sheet. The depth of groove 1 is sufficient to receive only a portion of the thickness of a split locking ring 8, which is seated in the groove. A loose flange ring 9 closely surrounds the peripheral edge of tube sheet 6 andhas an outer diameter somewhat less than the internal diameter of shell head 3. Flange ring 9 is provided with a groove Ill cut into its inner peripheral wall and in registration with groove 1 of the tube sheet, the depth of groove It) being suflicient to accommodate the portion of the thickness of locking ring 8 which extends beyond groove 1. When flange ring 9 is in looking engagement with tube sheet 6, its opposite side faces are substantially flush with the corresponding side faces of the tube sheet. Flange ring 9 is counterbored at It from its outer side face, that is, the side face farthest from the end of shell I, into communication with groove I0, so that groove It] forms an off-set shoulder in the counterbore II. The bottom of the counterbore is preferably chamfered, tapering at an angle from the wall of the counterbore to groove H] for purposes to be more fully explained hereinafter. When flange ring 9 is assembled on tube sheet 6, counterbore ll forms an annular recess l2 (Fig. 3) with the peripheral edge of the tube sheet. A compressible packing element I3 is positioned in recess l2 and the end of the tube sheet enclosed by a cap I4 having a peripheral flange l5 and a tubular sleeve l6 permanently aflixed to the face of the cap adjacent the outer face of tube sheet 6. Sleeve I6 is adapted to surround the peripheral edge of the tube sheet and. enter recess l3; Bolts I! extend through flange l5 and threadedly engage registering threaded apertures H3 in the outer face of flange ring 9. By screwing bolts IS in apertures l8, cap it is drawn toward the tube sheet and packing element l3 compressed between the leading edge of sleeve l6 and the surface formed by the chamfered bottom of counterbore l I and the outer'face of locking ring 8, to thereby prevent leakage of fluid from the tube nest into the shell of the exchanger. The leading edge of sleeve I6 is preferably chamfered to have an opposite slope to that of counterbore ll. Thus, upon'compression in recess 12, the packing will be forced generally in the direction of the peripheral edge of the tube sheet to thereby assure a tight seal. To compensate for wear of the packing element [3, it is only necessary to tighten up on bolts l1. Sleeve I6 is of suflicient length so that when the floating head is completely assembled and the packing tightly compressed, a chamber l9 will be provided between the adjacent faces of the tube sheet 6 and cap M, to permit passage of fluid from some of the tubes of the tube nest into chamber l9 and back through others of the tubes.

A series of guide plates 20 are positioned at spaced points about the inner wall of shell head 3 (Figs. 1 and 4) and in circumferential alignment with the outer peripheral edge of flange ring 9, which slides on guide plates 20 with movement of the floating head due to expansion and contraction of the tubes.

The floating head is assembled in the following manner: With shell head 3 removed, tube nest 5 bearing tube sheet 6 is inserted through shell I until the tube sheet extends beyond the floating head end of the shell. Flange ring 9 is slipped over and past the tube sheet in the direction of the end of the shell. Locking ring 8 is placed in groove 1 and flange ring 9 drawn back over the edge of the tube sheet until looking ring 9 is seated in groove ll] of the flange ring. Packing element I3 is inserted in recess l2 and sleeve l6 attached to cap l4 inserted into recess l2 behind the packing element l3. Bolts H are then inserted through flange l5 into apertures l8 and screwed down until the assembly is tight. Shell head 3 is then slipped over the floating head assembly and bolted tightly to flange 2 of the shell by means of bolts 4, completing the assembly of the floating head end of the exchanger.

By means of the form of the described floating head structure, substantially the entire surface area of the tube sheet is made available for the reception of tubes, since only that very'small annular portion occupied by groove 1 cannot be used for this purpose. This is an important improvement, particularly in the case of small diameter exchangers. For example, in the case of an exchanger having an internal shell diameter of approximately 8 inches, tube sheet 6 had an external diameter 'of 7% inches, and groove 1 a depth of approximately A; inch, the distance from the inner wall of the shell to the nearest point on the outermost annular row of tubes in the tube nest was substantially less than one tube diameter, or in this particular case, using inch 0. D; tubes the clearance was approximately seven-sixteenths of an inch.

It will be understood thatnumerous changes and alterations may be made in the size, form and arrangement of the details of the floating head structure of this invention without departing from the scope of the appended claims.

What I claim and desire to secure by Letters Patent is:

1. In a device of the character described, a floating head for tube nests comprising a tube sheet through with a plurality of tubes extend, a removable annular ring surrounding the peripheral edge of said tube sheet, registering grooves in the adjacent peripheral edges of said tube sheet and said annular ring, a split locking ring seated in both said grooves, an annular recess in said annular ring adjacent to the peripheral edge of said tube sheet, saidrecess extending from the-outer face of said annular ring into communication with the groove therein, a packing element positioned in said recess, a tubular cap encircling said tube sheet and extending into said recess into compressive relationship with said packing element, and means to draw said cap and said annular ring toward each other.

2. In a device of the character described, a floating head for tube nests comprising a tube sheet through which a plurality of tubes extend;

eral edge of said tube sheet, a packing element positioned in said recess, a tubular cap encircling said tube sheet and extending into said recess into compressive relationship with said packing element, the edge of said cap extending into said recess having a taper opposing that of the bottom of said recess, and means for drawing said cap and said annular ring toward each other.

3. In a device of the character described, a floating head for tube nests comprising a tube sheet through which a. plurality of tubes extend, a removable annular ring surrounding the peripheral edge of said tube sheet, registering grooves in the adjacent peripheral edges of said tube sheet and said annular ring, a split locking ring seated in both'said grooves, an annular recess in said annular ring adjacent to the peripheral edge of said tube sheet, said. recess extending from the outer face of said annular ring into communication with the groove therein, a packing element positioned in said recess, a tubular cap encircling said tube sheet and extending into said recess into compressive relationship with said packing element, and means to draw said cap and said annular ring toward each other, said means comprising an annular flange surrounding said cap and bolts extending through said flange into engagement with registering apertures in said annular ring. 7

4. In a device of the character described, a floating head for tube nests comprising a tube sheet through which a plurality of tubes extend, a removable annular ring surrounding the peripheral edge of said tube sheet, registering grooves in the adjacent peripheral edges of said tube sheet and said annular ring, a split locking ring seated in both said grooves, an annular recess in said annular ring adjacent to the peripheral edge of said tube sheet, said recess extending from the outer face of said annular ring into communication with the groove therein, a packing element positioned in said recess, and a cap for closing the outer face of said tube sheet, said cap including a tubular sleeve member having one end encircling the peripheral edge of said tube sheet and extending into said recess into compressive relationship with said packing element and the other end closed by a flanged cover plate, and bolt means connecting the flange on said cover plate with said annular ring for drawing said cap and said annular ring toward each other.

WILLIAM A. STOVER. 

